--  @testpoint:opengauss关键字chain(非保留)，作为函数名
--关键字不带引号-成功
drop function if exists chain;
create function chain(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/
--清理环境
drop function chain;

--关键字带双引号-成功
drop function if exists "chain";
create function "chain"(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/
--清理环境
drop function "chain";

--关键字带单引号-合理报错
drop function if exists 'chain';
create function 'chain'(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/

--关键字带反引号-合理报错
drop function if exists `chain`;
create function `chain`(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/